Wrong decision in 1990, not 1930

Date: 2012-01-04 01:32 pm (UTC)
The wrong decision was not made in 1930 - back then, there wasn't much choice.

It was made in 1990 when the transition to digital happened. Those guys made the stupid decision to carry on the old limitations instead of getting rid of them, because they're no longer needed.

The right approach would have been:

  • DVI and HDMI are defined to never have overscan. (Most likely, they drive digital displays which simply don't need it.)
  • Digital video material, e.g. DVD, mpg, avi, does not contain overscan. That is already the case, if you look at DVD rips or DVB (TV) recordings. We're good here.
  • If there is odd ancient video material which does contain overscan, the video player software or analog->digital converter software has to remove it. Configurable.
  • If you play digital content on an analog TV (mostly relevant in 1990s, not anymore), the analog output (e.g. Composite or VGA output of the graphics card) adds the overscan, as necessary for your TV. As it happens, graphics cards already do that for VGA monitors, so the existing system would simply by continued.

But no, this was probably all done by Hollywood guys who are a bit blurry in their mind, and we have to suffer from the fallout.

Lesson learned: If you design a new system, do not allow old limitations to creep into the new system, but go head-against-wall to remove them in the new system. Usually, there's a border between old and new systems where you can remove these old oddities. To not simply import the old stuff 1:1 and then deal with it somewhere else in the new system, but do it directly at the border.
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Matthew Garrett

About Matthew

Power management, mobile and firmware developer on Linux. Security developer at Google. Ex-biologist. @mjg59 on Twitter. Content here should not be interpreted as the opinion of my employer.

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